Coil and buffer spring system for a gun mount



Aug 13, 1957 E. H. cABANlss ETAL 2,802,401

COIL AND BUFFER-SPRING SYSTEM FOR A GUN MCUNT Filed May 25, 1953 Y ww Will/7' COIL AND BUFFER :SPRING SYSTEM FOR A 'GUN MUNT `Edward H. Cahaniss, Newton C. Garland, and Albert L. Hardy, Schenectady, .losephB.Gibbons, West Albany, andrieon "Webster Prayer, Schenectady, N. Y., assignors to the United States of America as `represented by the Secretary ofthe Air Force Application May 25, lasasenn No. 357,212

rcinm. (onse-sa) This invention relates `to agunmount and in particular to a dynamic automatic gun mount for aircraft.

An object of this invention is to provide a method of reducing the vibratory forces transmitted from the gun to the `support of an automatic gun.

Arfurther object of this inventionis to provide a gun mount capable of reducing the recoil forces by using a spring Iand buffer system so arranged and dimensioned that the buffer absorbs a portion ofthe recoil energy with the result that `the ring of .thesecond and each succeed- :ing shot `occurs Whilefthe gun is moving forward. This causes the gun to reverse its direction and start in the recoil direction with one-half the velocity of a free recoil.

A still further object of this invention is to provide a dynamic automatic gun mount provided with a movable support adapted to carry a gun in a recoil and counterrecoil direction, and With the movable support and the gun being constrained for movement on a relatively stationary support. Coil springs are mounted between the movable support and stationary support and are adapted to cooperate with Ia bulfer spring which is fixed to the stationary support and which is adapted to be actuated by the movable support. The movable support is driven in a recoil direction by the impulse from the firing of the gun. The bulfer spring assembly absorbs and stores that portion of the energy which was not stored by the coil springs so that the buifer spring and coil spring cooperate to drive the movable support in a counterrecoil direction at a frequency so as to be moving in a counterrecoil direction when the next recoil begins.

These and other objects will become more apparent when read in the light of the accompanying drawings and specification, which specification and drawings are not necessarily intended to limit the scope of the invention but is intended merely as an embodiment of the invention, but for such scope reference shall be made to the appended claim, wherein;

Fig. l is a plan view showing the arrangement of the springs on the stationary support with respect to the movable support.

Fig. 2 is a cross-sectional view taken on lines 2-2 of Fig. 1.

Fig. 3 is a right elevation side View of Fig. l.

Fig. 4 is a cross-sectional View taken on lines 4-4 of Fig. 1.

In the following description and in the claim parts will be identified by specific names for convenience, but they are intended to be as generic in their application to similar parts as the art will permit.

Referring to the drawings, the numeral generally designates a gun mounted on a yoke 12. Another portion of the gun is slidably mounted and constrained in a recoil and counterrecoil direction but is not shown since this forms no part of the invention. The yoke 12 is pivotally mounted on a support 14 on bolts or pins 18. The support 14 is bolted to longitudinal shafts 16. The shafts 16 are provided with reduced end portions 17 and 19 and an intermediate built-up portion 21. The builtrtice .up portion 21 is provided Iat its-ends with threaded portions so as toireceivestop nuts"22. Vertical supports 24 ares'ecurely fastenedtofa base 25, thesupports being provided -With bearings'Z adapted to be received in openings 27. Intermediate the vertical supports 24 are provided abutments 28. AAslidably mounted `ou the shaft portion 21 is a pair of bushings B0 which are adapted to contact either the -nut 22 or the abutment i28. Soft springs 32 are mounted :about "the-shafts landlbetween the slidable bushings 30. A longitudinal buffer shaft 34 is also mounted between the shafts 16 and is fixed to the support 14. The other endo'fthe shaft 34 is slidably mounted in a buffer assemblyhousing', thebuter 'assembly base 3S being xed toth'e fbasel25 by 'bolts or the like. A nut 39 is threadably mounted on shaft 34. The buffer assembly -housing 36 is-provided `with plungers `40 and 41 slidably `mountedon-the shaft 34 `and arefconstrained on the shaft by the friction ring springs 42. The buffer sleeve 44 is mounted on the buffer shaft 34 so that it is adapted to engage the plunger 40. 'Th'effactors determining the frequency ofvibration ofthe system is made possible by the dimension C=andfthe springs 42and 32 so as to have a particular frequency withrespec't tothe firing rate of the gun.

In operation, Lwhen the` gun is fired the impulse from lthe reeoillm'oves fthe `gun inalrearward direction, a portion of the energy being absorbed and stored by the friction ring spring 42, after the springs 32 have stored a portion of the energy. This is because the friction spring 42 will not come into play until the buffer sleeve 44 on the shaft 34 engages the plunger 40. The friction springs 42 and the coil springs 32 are constrained so that the friction springs absorb a portion of the energy of the free reco-il and then the springs 32 and 42 drive the gun in the counterrecoil direction. Due to the frequencies of springs 32 and 42 the gun is moving forward when the impulse from the next round is transferred to the movable support 12 and 14. In other words the buffer and spring systems have such a natural frequency with respect to the firing rate of the gun so as to have the gun moving in a counterrecoil direction when the next recoil is begun. A portion of the free recoil energy has been removed from the system by the buffer `spring and the gun will move iu the counterrecoil direction with approximately one-half a free recoil velocity when the second round is fired. This phenomena is the result of the spring system having a predetermined frequency and absorbing a predetermined amount of the energy. The firing of the second round causes the gun to reverse its direction and start to move in the recoil direction with approximately one-half the velocity of a free recoil. Thus approximately one-fourth the energy of the free recoil need only be stored by the recoil spring for the second and each succeeding shot of in which Vai-:free recoil velocity of the gun, Vp=velocity of the projectile, MP=mass of the projectile, and MG=mass of the gun. This velocity (VG) of the free recoil is approximately the theoretical velocity change of the gun dueto ring. If the gun is moving forward with a Velocity of VG/Z at the time the firing :impulse is transferred to the sliding or moving support, the recoil velocity will be VG/2. The velocity change will be VG/Z since the counterrecoil velocity is VG/Z yand will subtract from the VG, which is the free recoil velocity of the gun, thereby resulting in a recoil velocity of VG/ 2. Since the kinetic energy of the free recoil is 1/2MG-VG2 in which VG is actually VG/Z, the kinetic energy of the recoil of this 'system which need be stored would be'1/M rr(VG/2)2 which is equal to 1/2 (1A )MGVG2. t

Once the system stabilizes it is not necessary for the i butter system to remove energy since the coil springs yare selected to provide the desired counterrecoil` velocity.

This stabilized condition exists generally after the rst few rounds are red. The buier serves to restabilize the system if .the stabilization condition is lost during the continuous firing of the gun.

By this-'arrangement of parts a large reduction of the vibratory forces transmitted 'from the gun to the base is realized. This is the result of the low spring gradient in the recoil springs and that the storage of approximately only one-fourth of the free recoil energy in the recoil system will be required on the majority of shots.

It is apparent, the specific embodiment lshown above has been given by way of`illustration and not by way of limitation and that the structures |above described are subject to wide variation and modification without departing from the kscope or intent ofthe invention, all of which variations and modiiications areto' be included within the scope of the present invention. w

mediate the supports, a' pair of slidable bushings mounted on each of said shafts for engagement with said abutments,

each'en'd of said pair of shafts having a threaded portion, nuts threaded on said threaded portions for engaging the slidable bushings, coil springs mounted between each of the pairs of slidable bushings and normally biasing them 5 into engagement with said abutments, movable gun supporting means mounted on said pair of shafts, a gun disposed on said gunsupporting means, a buffer shaft having one end fixed tothe gunrsupporting means, a buier housing xedly mounted on the base, said butler shaft 10 being slidablymounted in the buffer housing, a buffer sleeve mounted on the buffer shaft a predetermined distance from said buffer housing, and a butler spring mounted around Isaid buier shaft Within said buer housing to forma coil and butler spring system with the coil springs, l5 said movable support meansrbeing driven in a recoil direction by tiring of said gun to actuate said coil springs and said butler spring whereby said coil and buler spring system reduces the vibratory forces transmitted to said base Y from said gun through said gun supporting, means.

g References'Cited inthe file of this Ypatent UNITED STATES PATENTSV 

